1. Making Proteins in the Powerhouse
B. Martin Hällberg, Nils-Göran Larsson 
Cell Metabolism 
Volume 20, Issue 2, Pages (August 2014)
DOI: /j.cmet
Copyright © 2014 Elsevier Inc. Terms and Conditions

2. Figure 1 The Gene Content of Mammalian mtDNA and Encoded mRNAs
The mammalian mtDNA contains only one longer noncoding region, denoted the displacement (D) loop region, which contains regulatory sequences needed for mtDNA replication and transcription. The mtDNA encodes 2 rRNAs (red boxes), 22 tRNAs (green boxes), and 11 mRNAs with 13 open reading frames (ORFs, blue boxes). The mRNAs contain no or very short 5′ noncoding sequences (yellow boxes) preceding the first translation initiation codon (AUA, AUU, or AUG). Furthermore, most mRNAs lack 3′ noncoding sequences (yellow boxes) between the stop codon (AGA, AGG, UAA, and UAG) and the short poly A tail. Two of the mRNAs (ND4/ND4L and ATP6/ATP8) are bicistronic, and each contains two partly overlapping ORFs. The structure of the human mRNAs are shown in the right panel.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2014 Elsevier Inc. Terms and Conditions

3. Figure 2 Posttranscriptional Maturation of mtDNA-Encoded RNAs
Each strand of mtDNA is transcribed as a long polycistronic transcript that is subsequently processed to release the individual mRNAs, tRNAs, and rRNAs. The mitochondrial RNase P consists of three subunits (MRPP1–MRPP3) and cleaves the primary transcript at the 5′ end of tRNAs. MRPP1 and MRPP2 are responsible for an N1 methylation of mitochondrial tRNAs. The tRNAs are released by cleavage at their 3′ ends by RNase Z (ELAC2). Yellow dots indicate RNA modifications.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2014 Elsevier Inc. Terms and Conditions

4. Figure 3 RNA Modifications Present in Mitochondria
Nucleobases with modifications that are found in mitochondrial RNA and discussed in the main text. The base modifications are highlighted with a lighter background. The cmnm5U modification is only present in bacteria and yeast mitochondria but is shown for comparison to the mammalian mitochondrial taurine-based modifications.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2014 Elsevier Inc. Terms and Conditions

5. Figure 4 Structure of the Large Subunit of the Mammalian Mitoribosome
Rendered from the 4.9 Å EM structure of the large subunit of the porcine mitoribosome (Greber et al., 2014). rRNA is colored in light beige, and ribosomal proteins that are not specifically denoted are colored in green. The RNA found to be bound to MRPL18 in the structure is denoted “RNA X.”
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2014 Elsevier Inc. Terms and Conditions

6. Figure 5
Biogenesis of the Mammalian Mitoribosomes and the Translation Cycle
The biogenesis of the mitoribosome requires that the 12S and 16S rRNAs are modified and assembled along with the ribosomal proteins. The large subunit of the mitoribosome is believed to be anchored to the inner mitochondrial membrane, and the translation cycle requires several factors for initiation, elongation, and termination. The membrane anchoring of the mitoribosome is believed to facilitate insertion of newly synthesized proteins into the inner mitochondrial membrane. The recycling of the mitoribosome is not shown.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2014 Elsevier Inc. Terms and Conditions